The French way to feel regret (3)
I believe the answer is:
rue
I believe this clue is a double definition.
'the french way' is the first definition.
('road' or 'street' in French)
'feel regret' is the second definition.
(I've seen this in another clue)
'to' acts as a link.
(Other definitions for rue that I've seen before include "Regret the bitter herb" , "Lament; a herb" , "repentance" , "Wish not to have been" , "Bitter-tasting herb" .)